This application claims the priority of German Patent Application No. 10051201.1 filed Oct. 16, 2000, the disclosure of which is hereby fully incorporated by reference herein.
The present invention pertains to a device for the two-dimensional application of free-flowing adhesive to a strip material, especially furniture edge banding, which is in motion relative to the device.
Devices of this type are used to apply adhesives two-dimensionally to furniture parts or strip-like substrates. The applicator head is usually mounted on a frame, and the strip material is conveyed past the applicator head by a transport device. During operation, the adhesive emerges from the elongated exit opening of the slot of the slot nozzle assembly and is dispensed onto the surface of the substrate being conveyed past the exit opening. The elongated exit opening of the slot is usually oriented crosswise or transverse to the direction of the relative motion between the applicator head and the substrate.
When so-called edge banding is glued to the edges of furniture, the procedure used so far according to the state of the art is to apply glue to the edge of a furniture part and then to press the edge banding, which is a flexible material strip of plastic, onto the previously glued edge of the furniture part. The glue is applied to the furniture part either by hand with considerable effort or with the help of automatic devices, which apply the adhesive by machine to the furniture parts. In both cases, considerable expense is involved.
The task of the present invention is to provide an application device and a guide device suitable for applying an adhesive directly to strip material or the like. In particular, an application device of this invention easily and precisely applies edge banding, molding, or the like keep parts or other workpieces.
According to the invention, a guide device guides the strip material past the exit opening of a slot nozzle along a defined path. The guide device includes a first guide element, which comes in contact during operation with the surface of the strip material opposite the surface to be glued, and at least one additional guide element, which comes in contact during operation with an edge of the strip material. The guide device is preferably attached in a removable manner to an applicator head having the slot nozzle.
With a simple design, the invention makes it possible to apply adhesive precisely and reliably in two dimensions to strip material, edge banding for furniture parts, molding strips, etc. The guide device according to the invention has a first guide element which ensures that the strip material to be glued is conducted past the exit opening of the slot nozzle either at an adjustable distance or in actual contact with the slot nozzle, so that the free-flowing adhesive is applied reliably and uniformly to the surface of the strip material to be glued. According to the invention, furthermore, the gluing as such and its quality can be influenced by adjusting the distance between the guide element and the exit opening, as a result of which the thickness of the applied glue can be controlled. Using at least one additional guide element, the strip material to be glued is also guided laterally along the desired path, to achieve the optimum orientation of the strip material to be glued relative to the exit opening of the slot nozzle. Through the attachment of the guide device directly to the applicator head, complicated support structures can be eliminated, and the guide device can be easily retrofitted to existing applicator heads. If an applicator head is also used for a different purpose which does not require the guidance of a strip-like substrate, the guide device can be easily removed from the applicator head. After the application of the adhesive to the strip material, the material can be bonded to other workpieces; for example, edge banding can be glued to furniture parts.
In a preferred embodiment of the invention, it is proposed that the guide device is supported by a swivel joint on the applicator head. As a result of this swiveling support, the guide device can move easily by virtue of its design so that, first, it can be adjusted to accommodate strip material of different thicknesses and, second, so that the first guide element can be moved between a contact position, in which the strip material to be glued is pressed against the nozzle assembly to create contact with the surface to be glued, and a rest position. In this latter position, production may be interrupted or gluing may be stopped, and the guide element makes no contact with either the slot nozzle or with the strip material.
According to a further aspect of this embodiment, the guide device maybe swiveled by a pneumatic cylinder. The first guide element is mounted at such as a distance from the swivel joint that, when the guide device is swiveled, the distance between the first guide element and the exit opening of the slot nozzle changes. In this way, the movement between the working position and the rest position can be easily produced.
Another embodiment is characterized by a preloading device to exert a preloading force on the guide device and/or the guide element toward a rest position, in which the guide element is held a certain distance away from the slot nozzle. The preloading device is preferably designed as a spring. As a result, in the case of an unwanted interruption in the operation (e.g. emergency shutdown), the strip material to be glued will not be pressed against the slot nozzle, which may be heated. Instead, the guide element will be swiveled into a rest position a certain distance away from the exit opening of the slot nozzle.
In a variant of the guide device according to the invention, it is provided that the first guide element is designed as a cylindrical bolt, which is set up essentially parallel to the exit opening. Such cylindrical bolts are easy to manufacture and provide reliable guidance with little friction. As alternatives, the first guide element could also be designed as a plate or as a rotating roll.
In another embodiment, it is proposed that two additional edge-guide elements be attachable to a support at variable distances from each other. These two edge-guide elements guide the substrate on both sides so that no unwanted shifting relative to the elongated exit opening of the slot can occur. Because the distances between the two elements is variable, it is also possible to adapt the guide to strip material or substrates of different widths.
It is also preferred that the support be mounted so that its position, along with that of the edge-guide elements, can be adjusted and then fixed in place on the guide device. This allows the two edge-guide elements to be aligned jointly relative to the strip material.
In another embodiment, the guide device is provided with a guide slot formed by plates a certain distance apart. The substrate or strip material is conveyed through this guide slot. With the help of this guide slot, it is possible to process, in particular, strip materials which have already been cut into sections. Such sections of material are fed reliably through the guide slot to the slot nozzle, even if the material is flexible or has the tendency to bunch up, as can be the case with edge banding.